<tr class="bg_table_row1"><td style="height:40px;"><div style="text-align:center;"><b>151</b></div></td><td><div><a href="index.php?section=problems&amp;id=151" style="text-decoration:none;" title="Click to view problem">
Paper sheets of standard sizes: an expected-value problem.
</a></div></td><td><div style="text-align:center;">1144</div></td></tr>
<tr class="bg_table_row2"><td style="height:40px;"><div style="text-align:center;"><b>152</b></div></td><td><div><a href="index.php?section=problems&amp;id=152" style="text-decoration:none;" title="Click to view problem">
Writing 1/2 as a sum of inverse squares
</a></div></td><td><div style="text-align:center;">610</div></td></tr>
<tr class="bg_table_row1"><td style="height:40px;"><div style="text-align:center;"><b>153</b></div></td><td><div><a href="index.php?section=problems&amp;id=153" style="text-decoration:none;" title="Click to view problem">
Investigating Gaussian Integers
</a></div></td><td><div style="text-align:center;">554</div></td></tr>
<tr class="bg_table_row2"><td style="height:40px;"><div style="text-align:center;"><b>154</b></div></td><td><div><a href="index.php?section=problems&amp;id=154" style="text-decoration:none;" title="Click to view problem">
Exploring Pascal&#39;s pyramid.
</a></div></td><td><div style="text-align:center;">596</div></td></tr>

<tr class="bg_table_row1"><td style="height:40px;"><div style="text-align:center;"><b>155</b></div></td><td><div><a href="index.php?section=problems&amp;id=155" style="text-decoration:none;" title="Click to view problem">
Counting Capacitor Circuits.
</a></div></td><td><div style="text-align:center;">828</div></td></tr>
<tr class="bg_table_row2"><td style="height:40px;"><div style="text-align:center;"><b>156</b></div></td><td><div><a href="index.php?section=problems&amp;id=156" style="text-decoration:none;" title="Click to view problem">
Counting Digits
</a></div></td><td><div style="text-align:center;">546</div></td></tr>
<tr class="bg_table_row1"><td style="height:40px;"><div style="text-align:center;"><b>157</b></div></td><td><div><a href="index.php?section=problems&amp;id=157" style="text-decoration:none;" title="Click to view problem">
Solving the diophantine equation <sup>1</sup>/<sub><var>a</var></sub>+<sup>1</sup>/<sub><var>b</var></sub>= <sup><var>p</var></sup>/<sub>10<sup><var>n</var></sup></sub> 
</a></div></td><td><div style="text-align:center;">627</div></td></tr>

<tr class="bg_table_row2"><td style="height:40px;"><div style="text-align:center;"><b>158</b></div></td><td><div><a href="index.php?section=problems&amp;id=158" style="text-decoration:none;" title="Click to view problem">
Exploring strings for which only one character comes lexicographically after its neighbour to the left.
</a></div></td><td><div style="text-align:center;">847</div></td></tr>
<tr class="bg_table_row1"><td style="height:40px;"><div style="text-align:center;"><b>159</b></div></td><td><div><a href="index.php?section=problems&amp;id=159" style="text-decoration:none;" title="Click to view problem">
Digital root sums of factorisations.

</a></div></td><td><div style="text-align:center;">752</div></td></tr>
<tr class="bg_table_row2"><td style="height:40px;"><div style="text-align:center;"><b>160</b></div></td><td><div><a href="index.php?section=problems&amp;id=160" style="text-decoration:none;" title="Click to view problem">
Factorial trailing digits
</a></div></td><td><div style="text-align:center;">756</div></td></tr>
<tr class="bg_table_row1"><td style="height:40px;"><div style="text-align:center;"><b>161</b></div></td><td><div><a href="index.php?section=problems&amp;id=161" style="text-decoration:none;" title="Click to view problem">
Triominoes
</a></div></td><td><div style="text-align:center;">507</div></td></tr>
<tr class="bg_table_row2"><td style="height:40px;"><div style="text-align:center;"><b>162</b></div></td><td><div><a href="index.php?section=problems&amp;id=162" style="text-decoration:none;" title="Click to view problem">
Hexadecimal numbers
</a></div></td><td><div style="text-align:center;">1305</div></td></tr>

<tr class="bg_table_row1"><td style="height:40px;"><div style="text-align:center;"><b>163</b></div></td><td><div><a href="index.php?section=problems&amp;id=163" style="text-decoration:none;" title="Click to view problem">
Cross-hatched triangles
</a></div></td><td><div style="text-align:center;">471</div></td></tr>
<tr class="bg_table_row2"><td style="height:40px;"><div style="text-align:center;"><b>164</b></div></td><td><div><a href="index.php?section=problems&amp;id=164" style="text-decoration:none;" title="Click to view problem">
Numbers for which no three consecutive digits have a sum greater than a given value.
</a></div></td><td><div style="text-align:center;">1349</div></td></tr>
<tr class="bg_table_row1"><td style="height:40px;"><div style="text-align:center;"><b>165</b></div></td><td><div><a href="index.php?section=problems&amp;id=165" style="text-decoration:none;" title="Click to view problem">
Intersections
</a></div></td><td><div style="text-align:center;">598</div></td></tr>
<tr class="bg_table_row2"><td style="height:40px;"><div style="text-align:center;"><b>166</b></div></td><td><div><a href="index.php?section=problems&amp;id=166" style="text-decoration:none;" title="Click to view problem">
Criss Cross
</a></div></td><td><div style="text-align:center;">964</div></td></tr>
<tr class="bg_table_row1"><td style="height:40px;"><div style="text-align:center;"><b>167</b></div></td><td><div><a href="index.php?section=problems&amp;id=167" style="text-decoration:none;" title="Click to view problem">
Investigating Ulam sequences
</a></div></td><td><div style="text-align:center;">429</div></td></tr>

<tr class="bg_table_row2"><td style="height:40px;"><div style="text-align:center;"><b>168</b></div></td><td><div><a href="index.php?section=problems&amp;id=168" style="text-decoration:none;" title="Click to view problem">
Number Rotations
</a></div></td><td><div style="text-align:center;">646</div></td></tr>
<tr class="bg_table_row1"><td style="height:40px;"><div style="text-align:center;"><b>169</b></div></td><td><div><a href="index.php?section=problems&amp;id=169" style="text-decoration:none;" title="Click to view problem">
Exploring the number of different ways a number can be expressed as a sum of powers of 2.

</a></div></td><td><div style="text-align:center;">905</div></td></tr>
<tr class="bg_table_row2"><td style="height:40px;"><div style="text-align:center;"><b>170</b></div></td><td><div><a href="index.php?section=problems&amp;id=170" style="text-decoration:none;" title="Click to view problem">
Find the largest 0 to 9 pandigital that can be formed by concatenating products.
</a></div></td><td><div style="text-align:center;">500</div></td></tr>
<tr class="bg_table_row1"><td style="height:40px;"><div style="text-align:center;"><b>171</b></div></td><td><div><a href="index.php?section=problems&amp;id=171" style="text-decoration:none;" title="Click to view problem">
Finding numbers for which the sum of the squares of the digits is a square.
</a></div></td><td><div style="text-align:center;">576</div></td></tr>

<tr class="bg_table_row2"><td style="height:40px;"><div style="text-align:center;"><b>172</b></div></td><td><div><a href="index.php?section=problems&amp;id=172" style="text-decoration:none;" title="Click to view problem">
Investigating numbers with few repeated digits.
</a></div></td><td><div style="text-align:center;">899</div></td></tr>
<tr class="bg_table_row1"><td style="height:40px;"><div style="text-align:center;"><b>173</b></div></td><td><div><a href="index.php?section=problems&amp;id=173" style="text-decoration:none;" title="Click to view problem">
Using up to one million tiles how many different "hollow" square laminae can be formed?
</a></div></td><td><div style="text-align:center;">2309</div></td></tr>
<tr class="bg_table_row2"><td style="height:40px;"><div style="text-align:center;"><b>174</b></div></td><td><div><a href="index.php?section=problems&amp;id=174" style="text-decoration:none;" title="Click to view problem">
Counting the number of "hollow" square laminae that can form one, two, three, ... distinct arrangements.
</a></div></td><td><div style="text-align:center;">1499</div></td></tr>
<tr class="bg_table_row1"><td style="height:40px;"><div style="text-align:center;"><b>175</b></div></td><td><div><a href="index.php?section=problems&amp;id=175" style="text-decoration:none;" title="Click to view problem">
Fractions involving the number of different ways a number can be expressed as a sum of powers of 2. 
</a></div></td><td><div style="text-align:center;">490</div></td></tr>
<tr class="bg_table_row2"><td style="height:40px;"><div style="text-align:center;"><b>176</b></div></td><td><div><a href="index.php?section=problems&amp;id=176" style="text-decoration:none;" title="Click to view problem">
Rectangular triangles that share a cathetus.
</a></div></td><td><div style="text-align:center;">526</div></td></tr>

<tr class="bg_table_row1"><td style="height:40px;"><div style="text-align:center;"><b>177</b></div></td><td><div><a href="index.php?section=problems&amp;id=177" style="text-decoration:none;" title="Click to view problem">
Integer angled Quadrilaterals.
</a></div></td><td><div style="text-align:center;">354</div></td></tr>
<tr class="bg_table_row2"><td style="height:40px;"><div style="text-align:center;"><b>178</b></div></td><td><div><a href="index.php?section=problems&amp;id=178" style="text-decoration:none;" title="Click to view problem">
Step Numbers
</a></div></td><td><div style="text-align:center;">803</div></td></tr>
<tr class="bg_table_row1"><td style="height:40px;"><div style="text-align:center;"><b>179</b></div></td><td><div><a href="index.php?section=problems&amp;id=179" style="text-decoration:none;" title="Click to view problem">
Consecutive positive divisors

</a></div></td><td><div style="text-align:center;">2831</div></td></tr>
<tr class="bg_table_row2"><td style="height:40px;"><div style="text-align:center;"><b>180</b></div></td><td><div><a href="index.php?section=problems&amp;id=180" style="text-decoration:none;" title="Click to view problem">
Rational zeros of a function of three variables.
</a></div></td><td><div style="text-align:center;">428</div></td></tr>
<tr class="bg_table_row1"><td style="height:40px;"><div style="text-align:center;"><b>181</b></div></td><td><div><a href="index.php?section=problems&amp;id=181" style="text-decoration:none;" title="Click to view problem">
Investigating in how many ways objects of two different colours can be grouped.
</a></div></td><td><div style="text-align:center;">464</div></td></tr>

<tr class="bg_table_row2"><td style="height:40px;"><div style="text-align:center;"><b>182</b></div></td><td><div><a href="index.php?section=problems&amp;id=182" style="text-decoration:none;" title="Click to view problem">
RSA encryption
</a></div></td><td><div style="text-align:center;">616</div></td></tr>
<tr class="bg_table_row1"><td style="height:40px;"><div style="text-align:center;"><b>183</b></div></td><td><div><a href="index.php?section=problems&amp;id=183" style="text-decoration:none;" title="Click to view problem">
Maximum product of parts
</a></div></td><td><div style="text-align:center;">1267</div></td></tr>
<tr class="bg_table_row2"><td style="height:40px;"><div style="text-align:center;"><b>184</b></div></td><td><div><a href="index.php?section=problems&amp;id=184" style="text-decoration:none;" title="Click to view problem">
Triangles containing the origin.
</a></div></td><td><div style="text-align:center;">423</div></td></tr>
<tr class="bg_table_row1"><td style="height:40px;"><div style="text-align:center;"><b>185</b></div></td><td><div><a href="index.php?section=problems&amp;id=185" style="text-decoration:none;" title="Click to view problem">
Number Mind
</a></div></td><td><div style="text-align:center;">760</div></td></tr>
<tr class="bg_table_row2"><td style="height:40px;"><div style="text-align:center;"><b>186</b></div></td><td><div><a href="index.php?section=problems&amp;id=186" style="text-decoration:none;" title="Click to view problem">
Connectedness of a network.
</a></div></td><td><div style="text-align:center;">677</div></td></tr>

<tr class="bg_table_row1"><td style="height:40px;"><div style="text-align:center;"><b>187</b></div></td><td><div><a href="index.php?section=problems&amp;id=187" style="text-decoration:none;" title="Click to view problem">
Semiprimes
</a></div></td><td><div style="text-align:center;">2763</div></td></tr>
<tr class="bg_table_row2"><td style="height:40px;"><div style="text-align:center;"><b>188</b></div></td><td><div><a href="index.php?section=problems&amp;id=188" style="text-decoration:none;" title="Click to view problem">
The hyperexponentiation of a number
</a></div></td><td><div style="text-align:center;">1680</div></td></tr>
<tr class="bg_table_row1"><td style="height:40px;"><div style="text-align:center;"><b>189</b></div></td><td><div><a href="index.php?section=problems&amp;id=189" style="text-decoration:none;" title="Click to view problem">
Tri-colouring a triangular grid
</a></div></td><td><div style="text-align:center;">500</div></td></tr>
<tr class="bg_table_row2"><td style="height:40px;"><div style="text-align:center;"><b>190</b></div></td><td><div><a href="index.php?section=problems&amp;id=190" style="text-decoration:none;" title="Click to view problem">
Maximising a weighted product

</a></div></td><td><div style="text-align:center;">1046</div></td></tr>
<tr class="bg_table_row1"><td style="height:40px;"><div style="text-align:center;"><b>191</b></div></td><td><div><a href="index.php?section=problems&amp;id=191" style="text-decoration:none;" title="Click to view problem">
Prize Strings
</a></div></td><td><div style="text-align:center;">1755</div></td></tr>

<tr class="bg_table_row2"><td style="height:40px;"><div style="text-align:center;"><b>192</b></div></td><td><div><a href="index.php?section=problems&amp;id=192" style="text-decoration:none;" title="Click to view problem">
Best Approximations
</a></div></td><td><div style="text-align:center;">432</div></td></tr>
<tr class="bg_table_row1"><td style="height:40px;"><div style="text-align:center;"><b>193</b></div></td><td><div><a href="index.php?section=problems&amp;id=193" style="text-decoration:none;" title="Click to view problem">
Squarefree Numbers
</a></div></td><td><div style="text-align:center;">713</div></td></tr>
<tr class="bg_table_row2"><td style="height:40px;"><div style="text-align:center;"><b>194</b></div></td><td><div><a href="index.php?section=problems&amp;id=194" style="text-decoration:none;" title="Click to view problem">
Coloured Configurations
</a></div></td><td><div style="text-align:center;">385</div></td></tr>
<tr class="bg_table_row1"><td style="height:40px;"><div style="text-align:center;"><b>195</b></div></td><td><div><a href="index.php?section=problems&amp;id=195" style="text-decoration:none;" title="Click to view problem">
Inscribed circles of triangles with one angle of 60 degrees
</a></div></td><td><div style="text-align:center;">366</div></td></tr>
<tr class="bg_table_row2"><td style="height:40px;"><div style="text-align:center;"><b>196</b></div></td><td><div><a href="index.php?section=problems&amp;id=196" style="text-decoration:none;" title="Click to view problem">
Prime triplets
</a></div></td><td><div style="text-align:center;">561</div></td></tr>

<tr class="bg_table_row1"><td style="height:40px;"><div style="text-align:center;"><b>197</b></div></td><td><div><a href="index.php?section=problems&amp;id=197" style="text-decoration:none;" title="Click to view problem">
Investigating the behaviour of a recursively defined sequence
</a></div></td><td><div style="text-align:center;">1423</div></td></tr>
<tr class="bg_table_row2"><td style="height:40px;"><div style="text-align:center;"><b>198</b></div></td><td><div><a href="index.php?section=problems&amp;id=198" style="text-decoration:none;" title="Click to view problem">
Ambiguous Numbers
</a></div></td><td><div style="text-align:center;">305</div></td></tr>
<tr class="bg_table_row1"><td style="height:40px;"><div style="text-align:center;"><b>199</b></div></td><td><div><a href="index.php?section=problems&amp;id=199" style="text-decoration:none;" title="Click to view problem">
Iterative Circle Packing
</a></div></td><td><div style="text-align:center;">496</div></td></tr>
<tr class="bg_table_row2"><td style="height:40px;"><div style="text-align:center;"><b>200</b></div></td><td><div><a href="index.php?section=problems&amp;id=200" style="text-decoration:none;" title="Click to view problem">
Find the 200th prime-proof sqube containing the contiguous sub-string "200"
</a></div></td><td><div style="text-align:center;">588</div></td></tr>

